Biophysical Society Thematic Meeting - June 28-July 1, 2015
New Biological Frontiers Illuminated by Molecular Sensors and Actuators
56-POS Board 56 Single-Biomolecule Fluorescence Enhancement by Gold-Nanoantenna Wenqi Zhao , Fan Liu, Xiaochaoran Tian, Meng Qiu, Lei Zhou, Yuanbo Zhang, Yanwen Tan. Fudan University, Shanghai, China. Single-molecule experiment can resolve molecular details of dynamic processes and has been applied extensively in biological studies and medical examinations. However, fluorescence from single biological macromolecules suffers from feeble signals that are not easily detected. We aim to utilize plasmonic nano-antennas, which can create highly enhanced local fields when pumped resonantly, leading to increased fluorescence intensities. Furthermore, to make the fluorescence enhancing process controllable and specific, we offered a novel method to conjugate fluorescent proteins of interests to gold nano-structures directly. Our method contains three parts: antenna- fabrication, surface passivation and gold-protein interaction. To replace conventional surface passivation procedure and facilitate nano-structure fabrication on insulating glass substrate, we demonstrated that CVD-graphene can be used to screen non-specific fluorescence signal while reducing charging effect during e-beam writing processes. For gold-protein conjugation, fluorescent proteins with Cysteine-tag can bind with gold-particle specifically via coordination bond between gold and thiol. In this step, pH is an important factor for binding process between gold-layer and protein molecules. The experimental fluorescence enhancement factors of fluorescent proteins coupled with gold nano-antenna are consistent with our simulation results. According to fano-effect, asymmetric-structures with controllable emission rate will provide stronger enhancement than bowtie, offering a potential improvement to our nano-antenna.
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